Electric discharge devices



y 1954 F. JACOBS, JR., ETAL 3,14 ,296

ELECTRIC DISCHARGE DEVICES 2 Sheets-Sheet 1 Filed Dec. 28, 1960 INVENTOR Frank Jacobs, Jr.

William H Savoge,dr.

BY AA? W ATTORNEY F. JACOBS, JR, ETAL 3,141,296

July 21, 1964 I ELECTRIC DISCHARGE DEVICES 2 Sheets-Sheet 2 Filed Dec. 28, 1960 INVENTOR Frank Jacobs, Jr.

William H.S0voge,Jr.

United States Patent 3,141,296 ELECTRIC DISCHARGE DEVICES Frank Jacobs, Jr., 2342 Mockingbird Lane, and William H. Savage, .Ir., 2040 W. Milier Road, both of Garland,

Tex.

Fiied Dec. 28, 1960, Ser. No. 78,962 11 Claims. (Cl. 6035.5)

This invention relates to an electric discharge device and more particularly to a power generating electric discharge device.

An object of this invention is to provide a new arid improved electric discharge device for generating power.

Another object is to provide a new and improved electric discharge device which utilizes shock waves produced in a liquid by an electric discharge therethrough to perform useful work.

Another object is to provide an electric discharge device for generating mechanical power, wherein the device is small and compact relative to its power output, and is characterized by economy of operation and simplicity of construction.

Another object is to provide a new and improved porpulsion device wherein thrust is developed by an electric discharge in a liquid.

Still another object is to provide a pump apparatus wherein an electric discharge in a liquid filled chamber of the pump causes the apparatus to pump liquid through an outlet of the pump and take in liquid through an inlet thereof, the electric discharge being repetitive to provide an intermittent pumping action.

A further object is to provide a pumping device including means for generating an electric discharge in a liquid filled chamber of the pump and valve means whereby the generation of the electrical discharge will first actuate the valve means to allow liquid to exhaust from the chamber through the pump outlet and then operate the valve means to allow liquid to flow through the pump inlet to replenish the chamber, the electric discharge being repetitive to establish a constant pumping action.

A still further object is to provide a linear actuator device comprising a piston and cylinder means wherein an electric discharge within a liquid filled chamber of the cylinder will cause reciprocation of a piston and piston rod slidably mounted on the cylinder to accomplish useful work.

A still further object is to provide a linear actuator comprising a piston and cylinder means with the chamber between the cylinder head and piston being liquid filled and wherein an electric discharge within the chamber slidably moves the piston and causes a piston rod connected thereto to move outwardly of the chamber, the piston being returnable to its initial position by the decrease in pressure created in the chamber by the pistons sliding movement and the cylinder head being a floating head which is immovable during the pressure development but moves toward the piston when the vacuum develops in the chamber as the piston rod moves outwardly, thereby obtaining a larger piston stroke and greater eificiency than would be obtainable with a fixed cylinder head.

Additional objects and advantages of the invention will be readily apparent from the following description of a device constructed in accordance with the invention, and with reference to the accompanying drawings thereof, wherein:

FIGURE 1 is a perspective view of a water craft provided with a propulsion device embodying the invention;

FIGURE 2 is an exploded perspective sectional view showing the chamber body of the propulsion device of FIGURE 1;

FIGURE 3 is a schematic diagram of a typical electrical circuit for operating the propulsion device;

FIGURE 3A is an enlarged perspective view of the air gap switch of FIGURE 3;

FIGURE 4 is a perspective sectional view of an electrically actuated liquid pump embodying the invention;

FIGURE 5 is a perspective sectional view of a linear actuator embodying the invention; and,

FIGURE 6 is a perspective sectional view of a modified form of the linear actuator.

Referring particularly to the drawings, the basic concept and principle of operation of the invention is illustrated by the propulsion device 9 illustrated in FIGURES 1 through 3. The propulsion device 9 includes a pair of electrodes 1d and 11 mounted in the walls of a rigid, pressure proof cylindrical body 12 immersed in a liquid and defining a chamber or internal bore having a circular transverse cross section and open at the ends 13 and 14. The forward portion of the internal bore is divergent toward the end 14 of the body and the aft portion is straight with uniform cross section. The electrodes 10 and 11 are elongate and of circular cross section and are disposed within hollow cylindrical insulators 15 and 16, respectively, and are coaxial therewith. The insulators are disposed within accommodating transverse bores extending through the walls of the cylindrical body and secured by any suitable means in the bores in fluid tight engagement therewith. The bores are circular in cross section to accommodate the insulators and are diametrically disposed within the cylindrical body so that their faces Na and Ila are separated a predetermined distance to provide a spark gap. Although, as illustrated, both electrodes are provided with an insulator to prevent an electrical short through the chamber structure, it is apparent that an insulator may be provided for the positive electrode only, if desired.

An electric discharge between the two electrodes may be produced by a suitable circuit wherein a high voltage is repetitively impressed across the electrodes to cause an electric discharge or arc across the gap between the electrode faces. When an are or electrical discharge occurs in the gap between electrodes, a shock wave having a spherical wave front is generated in the liquid. In addition, vaporization of liquid occurs creating a high pressure wave and rapidly expanding gaseous media. The shock wave and the pressure wave propagate through the internal bore of the cylinder to the forward and aft portions thereof. Due to the divergent forward portion of the bore, the pressure and shock waves are rapidly attenuated in the forward portion of the chamber providing little or no forward thrust. On the other hand, liq uid is forced out the after portion of the chamber with high velocity, thereby creating thrust in the forward direction. As the cylindrical body is propelled forward, the liquid which was displaced in the vicinity of the electrodes is replaced by liquid entering through the forward flaring end of the chamber. As this cycle of operation is repeated, 21 substantially constant thrust is imparted to the cylindrical body which, if free, moves forwardly through the liquid.

The divergence of the forward portion of the internal bore obviates the need for mechanical valving as would otherwise be necessary to prevent liquid flow in the forward direction. However, mechanical valving may be provided if desired. The valving would, of course, require rapid operation to close and open in the proper sequence to resist the pressure and shock wave propagation forward and to provide for fluid replacement in the bore with a minimum drag. While the after portion of the internal bore is disclosed as being straight, it may also be divergent or convergent depending on the desired mode of operation of the forward valving incorporated in the device.

A typical application of the propulsion device 9 as an outboard motor for a boat 17 is illustrated in FIG- URE 1 wherein steering is accomplished by a conventional rudder, not shown. The cylindrical body 12 is supported by a V-shaped bracket having arms 13 and 1% provided at their extremities with clamp members fail and 21 for gripping the transom of the boat. An areaate plate 22 at the apex of the V-bracket conforms with the shape of the cylindrical body which is attached thereto by bolts 23 or any other suitable means. The longitudinal axis of the unit is parallel with the keel of the boat to provide forward thrust to the craft. A fin 24.- may be integrally formed with the cylinder 12 or a tached thereto at its bottom surface. While in the particular illustration, the unit is rigidly attached to the craft, it is apparent that the whole unit may be pivotally mounted to the craft to provide a steering means therefor. Also, the propulsion unit is obviously adaptable for use with either surface or underwater vehicles and a number of such units may be incorporated within the structure of a craft, or on appendages thereof, such as hydro-foils, to provide suitable propulsion of the craft.

A schematic diagram illustrating a typical circuit for producing a discharge between the electrodes is illustrated in FIGURE 3. The circuit includes a power sup ply 25 providing a high voltage, direct current output from a relatively low voltage input. One side of a resistance 26 is connected to one side of the power supply by mcans of a conductor 27. The other side of the resistance is connected to one side of a capacitance bank comprised of a series parallel grouping of condensers 28, 29, 3t) and 31 through a conductor 32, choke 33 and conductors 34- and 35. The other side of the capacitance bank is connected to the other side of the power supply 25 through ground.

The capacitance bank is connected to an air gap switch 36 by the conductors and 54. The air gap switch comprises two fixed electrodes 4i? and 41 with an air gap separating the electrodes, an interrupted insulating disc 42 mounted to rotate between the electrodes, and a motor 43 for imparting rotation to the disc. The electrode is connected to one side of the capacitance bank by the conductors 34 and 3S and the electrode 41 is connected by the conductor 44a to the electrode 10 of the propulsion device. The other electrode 11 of the propulsion device is connected to the other side of the capacitance bank through the conductor l tb and ground. The electrodes of the switch 36 are spaced to allow current discharge between them when air is the dielectric therebetween. The insulating disc is fabricated of material having a dielectric constant considerably higher than that of air and is provided with circumferentially spaced notches in its periphery to form the blades 42a. The disc is mounted on the end of the shaft 44 so positioned that the blades of the disc move through the gap between the electrodes ll) and ll as the disc is rotated. During the time interval that a blade of the disc is between the electrodes, no discharge can occur, and the capacitance bank will be charged by the power supply. However, when a blade of the disc moves away from between the electrodes, an electric arc passes between the electrodes thereby connecting the electrodes ltl and 11 of the propulsion device across the capacitance bank which discharges to cause an electric discharge or arc across the gap between them. The motor, of course, is adapted to rotate the insulating disc at a rate commensurate with the discharge requirements of the propulsion device.

It is apparent that a symmetrical straight chamber in the cylindrical body of FTGURE 2 would cause an equal quantity of liquid to be discharged from both ends of the chamber when an electrical discharge occurs acrnqe the electrode gap, thereby producing little or no 41- thrust. The particular configuration of the chamber obviously controls the character of the thrust produced by the unit and the selection of a chamber configuration would be largely dictated by the proposed application of the device. Another control factor resides in the arrangement of electrodes in the unit and a variety of arrangements, other than that disclosed in FIGURE 2, are obviously suitable.

A modified form of the device, useful as a liquid pump is illustrated in FIGURE 4. The pump comprises a cylindrical housing 5% defining a chamber of circular cross section and a pair of electrodes 51 and 52 with associated insulators 53 and 54, respectively, disposed in diametrically opposed transverse bores in the housing. The internal wall of the chamber may be threaded at the end portions 5% and 5% of the housing for attachment to conduits or other devices whereby liquids to be pumped may flow into the pump at the end 50a and be discharged from the pump at the end Bill).

The internal wall of the cylindrical housing is provided with annular radially extending shoulders 55 and and 56 on opposite sides of the electrodes and spaced therefrom. From each end of the cylinder body, bores of large and equal diameter extend inward an equal distance to provide annular shoulders 69 and 61, re spectively. From each shoulder 60 and 61, bores of equal intermediate diameter extend inward to form radial shoulders 55 and 56. The axes of the various diameter bores which define the internal chamber of the cylinder are coaxial with the cylinder body axis so that the chamber is symmetrical with respect to the cylinder axis.

Circular walls 65 and 66 of a diameter equalling that of the large diameter bores extend transversely in the chamber and abut the annular shoulders 60 and 61. Circular walls 67 and 63 of a diameter equalling that of the intermediate diameter portions of the chamber extend transversely in the chamber and abut the shoulders 55 and 56.

A valve 6? has a stern 7d and conical portion 71 which coacts with the beveled seat 71a of the wall 66. The valve 69 acts as an inlet check valve to allow liquid to flow from the inlet end 500: of the cylinder to the electrodes through the central aperture of the wall. The stem 70 of the valve 69 is slidably mounted in an accommodating aperture in the wall 68 and is coaxial with the cylinder. The base of the conical portion is enlarged with respect to the stem 7tl so that the base of the head forms an annular shoulder 72. The valve stem is biased toward the inlet end of the cylinder by a coil spring 73 disposed about the stem with one end abutting the shoulder 72 and its other end abutting the wall 68. In its normally biased position, the conical portion of the valve closes the aperture in the wall 66.

A similar valve '79 having a stem 30 and a conical portion 81 which coacts with the beveled seat 81a of the wall 67 serves as an outlet check valve which allows liquid to ilow through a central aperture of the wall 67 to the outlet end 5% of the cylinder. The stem is slidably mounted in an accommodating aperture in the wall 65. A coil spring 82 disposed about the stem 80 has one end abutting the wall 65' and its other end abutting the shoulder 83 of the valve at the base of the conical portion. In normal position, the conical portion 81 engages the seat 31a of the wall 67 and prevents passage of liquid through the central aperture thereof. The walls 68 and 65 have slots 85 to permit flow of liquid therethrough. The walls 66 and 67 define the ends of the electrode chamber 86 wherein liquid may be confined.

When an electric discharge is caused to occur in the electrode chamber between the electrodes by the application of a voltage impulse across the electrodes, the shock and pressure waves created increase the pressure within the electrode chamber. When the pressure reaches the cracking pressure of the outlet check valve, the biasing force of the spring 82 is overcome and the outlet valve opens to allow liquid to be discharged from the electrode chamber through the outlet end of the housing. The increased pressure also tends to hold the inlet valve in closed position. The loss of discharged liquid from the electrode chamber due to the opening of the outlet valve then decreases the pressure within the chamber and the resulting pressure differential between the electrode chamber and the adjacent chamber portions cause the outlet valve to close and the inlet valve to open. The liquid entering from the inlet end 50a recharges the electrode chamber volume and lowers the pressure ditferential be tween the inlet end and the electrode chamber, thus permitting the spring 73 to move the valve 69 to closed position. The next succeeding electric discharge between the electrodes will then cause this sequence of operations to be repeated to cause liquid to flow from the inlet end 50a to the outlet end 50b. The voltage is applied across the electrodes at a proper frequency to assure sustained pumping action by any suitable means, such as the device illustrated in FIGURE 3.

Referring now to FIGURE 5, the linear actuator 89 includes a cylinder 90 of circular cross section closed at one end by a transverse wall or cylinder head 91 integrally formed therewith and a plug 92 threadly connected to the other end of the cylinder. The plug is provided with a central circular bore through which slidably extends the piston rod 93 of a piston 94 slidably mounted in the cylinder. A fixed quantity of fluid is contained between the cylinder head and the piston and to prevent its movement past the piston, the piston is provided with an exterior annular groove 94a in which an O-ring 95 or other suitable sealing means is disposed to seal between the cylinder and the piston head. The piston is biased toward the cylinder head by a coil spring 96 disposed about the piston rod and having one end abutting the piston head and its other end abutting the end plug 92.

A pair of electrodes 97 and 98 with associated insulators 97a and 98a are disposed within diametrically opposed transverse bores extending through the cylinder wall near the cylinder head end of the cylinder. When an electrical discharge is caused to occur through the liquid between the two electrodes by a suitable circuit means, shock and pressure waves are created in the liquid which impinge on the cylinder head and piston head. The resulting shock and pressure front moves the piston and its rod outwardly against the resistance of the spring 96. The piston rod is threaded at its free end portion whereby it may be attached to any desired device or tool, such as a die, shear, or the like.

The piston is returned to its initial position in the cylinder, after the energy of the shock and pressure waves has been absorbed, by the reaction force exerted by the spring 96 and, in the event the are between the electrodes has caused any of the liquid to be vaporized, by the subsequent condensation of such liquid. A trunnion 99 is mounted on the cylinder to provide mounting or support means for the device but any other means providing suitable support may be provided.

A modified form of linear actuator is illustrated in FIGURE 6 and is particularly suited for use where a longer stroke than that yielded by the actuator of FIG- URE 5 is required. The linear actuator 100 comprises a cylinder 101 and piston 102 substantially identical with those employed in the embodiment of FIGURE 5. The internal wall of the cylinder at one end is provided with an internal annular flange 103 defining a circular aperture for accommodating a floating piston 104 slidably disposed therein. A second internal annular flange 105 is provided on the internal wall of the cylinder closely adjacent the annular flange 103 but longitudinally spaced therefrom. Between the flanges an 'O-ring 106 is disposed to providee a seal between the cylinder and the floating piston.

The floating piston 104 comprises a hollow cylindrical member 107 having a radially extending flange 108 at the end of the piston which is disposed within the cylinder to engage the annular flange of the cylinder thereby limiting outward movement of the floating piston. Within the hollow cylinder 107 are disposed a cylindrical tubular electrode 110 and a rod electrode 111 separated by a cylindrical insulator 112. The central rod electrode is the positive electrode and is of equal length with the insulator with their ends co-planar. However, the tubular negative or ground electrode is slightly shorter than the rod electrode and insulator and its end which is disposed within the cylinder extends beyond the ends of the positive rod electrode and insulator over which it is sleeved so as to provide an arc gap between the electrode ends which is not interrupted by the insulator. The electrodes, the insulator, and the hollow cylindrical mem her 107 are secured against movement relative to one another, in any suitable manner, as by bonding or the like.

Within the cylinder 101 between the floating piston in the cylinder head and the piston 102 is disposed a fixed volume of liquid. An O-ring 11d fitted within an external annular groove 117 of the piston provides an efiiective seal between the cylinder and the piston. The piston rod 119 extends slidably through a bore formed in the plug 120 which is threadedly connected to the cylinder end and is shown to be threaded at its free end to provide a fitting attaching means. It is to be understood, of course, that the piston rod extremity may be configured to provide adaptation for any use of the actuator as may be desired. A trunnion 121 mounted on the cylinder near the cylinder head provides means for supporting the device in an operational position, however, any other suitable support means may be provided.

Between the end plug 120 and the piston head the cylinder chamber is filled with a compressible gas Which is sealed therein by the O-ring 116 and a similar O-ring 122 disposed in an annular groove 123 in the internal Wall of the piston rod accommodating bore of the end plug. As an electric discharge is caused to occur across the arc gap through the liquid between the electrodes, the resulting shock and pressure waves hold the floating piston fixed against the cylinder flange 105 in the cylinder head and actuate the piston M2 to move the piston rod outwardly of the cylinder, which outward movement of the piston is limited by compression of the gas between the end plug and piston head. The vaporization of liquid in the electrode gap area and condensation thereof subsequently decreases the pressure in the liquid chamber and creates a partial vacuum as would also normally ocour in the linear actuator of FIGURE 5. However, because of the floating piston in the cylinder head, the amount of pressure decrease is reduced since the floating piston is urged to move inwardly of the cylinder by the developing vacuum in the liquid chamber. Consequently, the effect of the vacuum Within the liquid chamber on the movement of the piston and piston rod is strictly curtailed so that a larger piston stroke is obtainable than if the cylinder head were fixed. The return stroke of the piston is accomplished by the adiabatic compression and subsequent expansion of the gas in the chamber between the end plug and piston head which provides the energy to restore the working piston, the floating piston, and the liquid betwen the pistons to their original positions. Thus, itwill be seen that the floating piston type cylinder head in the linear actuator of FIGURE 6 will provide for a longer piston stroke and greater efficiency than is other- Wise obtainable with a fixed cylinder head.

It will also be seen that the mechanical power generating device which is basically described herein and comprises a liquid filled chamber with means for producing an electric discharge within the chamber to create shock and pressure waves in the liquid may find useful application in a variety of devices. While water is generally suitable as the liquid medium, it is to be understood that other dielectric liquids may prove even more satisfactory in certain applications.

It will also be seen that the particular chamber configuration and arrangement of electrodes controls the character of the shock and pressure waves created by the electric discharge so that the chamber configuration and electrode arrangement may be selected, as desired, to adapt the device to a particular application.

It will further be seen that the embodiments of the invention described herein are not inherently limited in size or in useful work output. Relative to the power developed, they are small and compact and among their inherent advantages are simplicity of construction, economy of operation, high speed operation, and close control of output.

The foregoing description of the invention is explanatory only, and changes in the details of the construction illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. A device comprising: a body having a chamber, said chamber containing liquid; means for generating an electric discharge within the liquid of the chamber between two fixed points in the chamber to cause the production of shock and pressure waves within the liquid, said body having means exposed to the shock and pressure waves in the liquid, said chamber being longitudinal in form and open at forward and rear ends thereof, said body having an internal wall defining the chamber, said chamber being of smaller cross-sectional area at said rear end than at said forward end, said internal wall adjacent the forward end or said body being divergent outwardly toward said forward end whereby a forward thrust is imparted to said body when an electric discharge is generated within the liquid.

2. A device comprising: a body having a chamber, said chamber containing liquid; means for generating an electric discharge within the liquid of the chamber between two fixed points in the chamber to cause the production of shock and pressure waves within the liquid, said body having means exposed to the shock and pressure waves in the liquid, said chamber being longitudinal in form and open at both ends and said means exposed to the shock and pressure waves within the liquid comprises an exhaust valve means disposed on one side of the electric discharge generating means and operable in response to the shock and pressure waves in said liquid to allow liquid to flow from said chamber and an inlet valve means disposed on the opposite side of the electric discharge generating means and operable in response to the decrease in pressure within said chamber caused by the outflow of liquid to allow liquid to fiow into the chamber.

3. A device comprising: A body having a chamber, said chamber containing liquid; means for generating an electric discharge within the liquid of the chamber between two fixed points in the chamber to cause the production of shock and pressure waves within the liquid, said body having means explosed to the shock and pressure waves in the liquid, said chamber being longitudinal in form and closed at both ends, and said means exposed to the shock and pressure waves comprises a piston slidably mounted within the chamber and disposed on one side of the liquid within the chamber, said piston having means slidably extending through one of the closed ends of the chamber.

4. A propulsion device for use in a liquid comprising a body defining a longitudinal chamber open at forward and rear ends, said chamber being of smaller cross sectional area at said rear end than at said forward end, an internal wall of the body defining the chamber converging from the forward end of the chamber toward the rear end of the chamber about a longitudinal axis of said chamber; and means disposed centrally within said chamber for generating an electric discharge between two fixed points in said chamber whereby when said propulsion device is disposed within a body of liquid, shock and pressure waves are created in the liquid by electric discharges to cause the expelling of liquid from the rear end of the chamber and the creation of thrust in a direction opposite to that of the expelled liquid.

5. A device comprising a hollow cylindrical body having a cylinder head closing one end of the cylindrical body and an end plug connected to the other end of said body to define a closed chamber, said end plug having an aperture coaxial with the cylinder axis; a piston slidably mounted within said cylinder body, said piston having means slidably extending through said aperture; a portion or" said chamber between the cylinder head and the piston being liquid filled; means for generating an electrical discharge within the liquid in said chamber to cause the production of shock and pressure waves within the liquid and actuation of the piston to move said piston means outwardly of the chamber; and biasing means within said chamber between the piston and the end plug for biasing the piston toward said cylinder head.

6. The device of claim 5 wherein said biasing means is a coil spring disposed about the piston means with one end abutting the end plug and its other end abutting the piston.

7. The device of claim 5 wherein said biasing means is a compressible gas.

8. An apparatus for pumping liquid comprising a cylindrical body defining a longitudinal chamber having an outlet end and an inlet end through which liquid may be admitted into the chamber; means disposed centrally within said chamber for generating successive electric discharges when liquid is disposed in the chamber whereby shock and pressure waves are produced in the liquid by each electric discharge; a first valve means disposed within said chamber to one side of said electric discharge generating means and operable in response to shock and pressure waves produced by each electric discharge to allow liquid to How from the chamber through said outlet end after each electric discharge; and a second valve means disposed within said chamber on the side of the electric discharge means opposite said first valve means, said second valve means being operable in response to the decrease in pressure caused by the outfiow of liquid from said chamber to allow liquid to fiow into the chamber through said inlet end after each of said discharges.

9. A device comprising a cylindrical body defining a longitudinal chamber; an end plug attached to the cylindrical body and closing one end of the chamber, said end plug having an aperture extending therethrough; a cylinder head closing the other end of said chamber; a floating piston extending through said cylinder head and slidably mounted in fluid tight relationship therewith; a piston slidably mounted within the chamber, said chamber being liquid filled between the piston and the cylinder head; means attached to the piston and slidably extending through the aperture in said end plug in fiuid tight rela tionship with said end plug; means for generating an electric discharge within the liquid in said chamber to cause the production of shock and pressure waves within the liquid and actuation of the piston toward said end plug whereby the decrease in pressure in the liquid filled portion of the chamber effected by the actuation of the piston causes the floating piston in the cylinder head to move inwardly into the chamber thereby reducing the decrease in pressure and increasing the amount of movement of the piston toward the end plug; and means for biasing said piston toward said cylinder head.

10. The device of claim 9 wherein said floating piston has an aperture extending therethrough in the longitu- 9 10 dinal direction of said chamber and the means for genof the insulator and other electrode to provide a gap erating an electric discharge is disposed within the aperbetween the electrodes. ture of said floating piston in fluid tight relationship therewith. References Cited in the file of this patent 11. The device of claim 10 wherein the means for 5 UNITED STATES PATENTS generating an electric discharge comprises a tubular electrode and an oppositely charged rod electrode disposed 1940775 Smith 1933 2,403,990 Mason July 16, 1946 within said tubular electrode and separated therefrom by 2 585 810 Maninckmdt Feb 12 1952 a tubular insulator, one end of one of said electrodes 219461217 Fruengel July 1960 extending into said chamber and beyond the extremities 

1. A DEVICE COMPRISING: A BODY HAVING A CHAMBER, SAID CHAMBER CONTAINING LIQUID; MEANS FOR GENERATING AN ELECTRIC DISCHARGE WITHIN THE LIQUID OF THE CHAMBER BETWEEN TWO FIXED POINTS IN THE CHAMBER TO CAUSE THE PRODUCTION OF SHOCK AND PRESSURE WAVES WITHIN THE LIQUID, SAID BODY HAVING MEANS EXPOSED TO THE SHOCK AND PRESSURE WAVES IN THE LIQUID, SAID CHAMBER BEING LONGITUDINAL IN FORM AND OPEN AT FORWARD AND REAR ENDS THEREOF, SAID BODY HAVING AN INTERNAL WALL DEFINING THE CHAMBER, SAID CHAMBER BEING OF SMALLER CROSS-SECTIONAL AREA AT SAID REAR END THAN AT SAID FORWARD END, SAID INTERNAL WALL ADJACENT THE FORWARD END OF SAID BODY BEING DIVERGENT OUTWARDLY TOWARD SAID FORWARD END WHEREBY A FORWARD THRUST IS IMPARTED TO SAID BODY WHEN AN ELECTRIC DISCHARGE IS GENERATED WITHIN THE LIQUID. 